Many telephone handsets are equipped with a device termed an HAC coil, or Hearing Aid Compatible coil. The HAC coil acts as an antenna, and broadcasts the audio signal received by the handset to a nearby hearing aid, which contains a similar coil, called a T-coil, which acts as a receiving antenna. This arrangement allows the hearing aid to receive the same audio signal received by the loudspeaker within the handset.
One or more of the Inventors herein attempted to improve signal transfer between the HAC coil and the T-coil. This attempt led to an unexpected improvement in the handset, which allowed hearing-impaired persons to more readily understand speech delivered by the improved handset, without use of the T-coil or the associated hearing aid.